Azole-functionalized silica adsorbent

ABSTRACT

A functionalized silica sorbent is described. The sorbent comprises mesoporous silica nanoparticles having a surface functionalized with a conjugated system comprising an azole and a phenyl. The surface may be functionalized by a Cu-catalyzed click reaction. The nanoparticles have an average particle size of 10-80 nm, and may be used to adsorb phenolic contaminants from aqueous solutions.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a Continuation of U.S. application Ser. No.16/296,480, now allowed, having a filing date of Mar. 8, 2019.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTORS

Aspects of this technology are described in an article Tanimu, A.;Jillani, S. M. S.; Alluhaidan, A. A.; Ganiyu, S. A.; and Alhooshani, K.,“4-phenyl-1,2,3-triazole functionalized mesoporous silica SBA-15 assorbent in an efficient stir bar-supported micro-solid-phase extractionstrategy for highly to moderately polar phenols,” Talanta, 194 (2019)377-384, doi: 10.1016/j.talanta.2018.10.012, which is incorporatedherein by reference in its entirety.

STATEMENT OF ACKNOWLEDGEMENT

The inventors acknowledge the support provided by the ChemistryDepartment of King Fahd University of Petroleum and Minerals (KFUPM).

BACKGROUND OF THE INVENTION Technical Field

The present invention relates to a functionalized silica sorbent, amethod of making, and a method of using to adsorb a contaminant from anaqueous solution.

Description of the Related Art

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Phenols, a type of aromatic compound that has a hydroxyl group (—OH)bonded to a phenyl ring, have many applications in pharmaceuticalindustries, food companies, and petrochemicals industries, and arecommonly found in polymer, dyes, and pesticides. See T. Dohi, A.Maruyama, N. Takenaga, K. Senami, Y. Minamitsuji, H. Fujioka, S. B.Caemmerer, Y. Kita, A chiral hypervalent iodine(iii) reagent forenantioselective dearomatization of phenols, Angew. Chemie Int. Ed. 47(2008) 3787-3790; X. Ye, A. M. Bishop, L. L. Needham, A. M. Calafat,Automated on-line column-switching HPLC-MS/MS method with peak focusingfor measuring parabens, triclosan, and other environmental phenols inhuman milk, Anal. Chim. Acta. 622 (2008) 150-156; and A. Llop, E.Pocurull, F. Borrull, Evaluation of the removal of pollutants frompetrochemical wastewater using a membrane bioreactor treatment plant,Water. Air. Soil Pollut. 197 (2009) 349-359, each incorporated herein byreference in their entirety. Additionally, phenol derivatives, such aspentachlorophenol, are used as a preservative in sawmills, and the slowdegradation of lignin in the pulp and paper industry generates phenols.The treatment of drinking water and swimming pool water can lead to theformation of chlorophenols. See A. V. Kolliopoulos, D. K. Kampouris, C.E. Banks, Indirect electroanalytical detection of phenols, Analyst. 140(2015) 3244-3250, incorporated herein by reference in its entirety.These phenolic compounds are mostly toxic and generally unpleasant, evenat very low concentrations. See G. Galati, P. J. O'Brien, Potentialtoxicity of flavonoids and other dietary phenolics: significance fortheir chemopreventive and anticancer properties, Free Radic. Biol. Med.37 (2004) 287-303, incorporated herein by reference in its entirety. Forexample, upon exposure to the skin or when inhaled, they can induce ahigh degree of skin and eye irritation. In some cases, long-term effectsinclude liver and heart failure. As such, the US EnvironmentalProtection Agency (EPA) and the European Union (EU) have classifiedseveral phenolic compounds as priority pollutants with a maximum limitof gross phenols in drinking water being 0.5 μg/L. See 1. Rodriguez, M.P. Llompart, R. Cela, Solid-phase extraction of phenols (Review), J.Chromatogr. 885 (2000) 291-304, incorporated herein by reference in itsentirety.

Because of these harmful effects of phenols and the stringentregulations limiting phenolic compounds in drinking water, there hasbeen an intensifying interest in finding new sorbents for phenoliccompound extraction in addition to emerging analytical methods for itsdetermination. Silica based sorbents were among the first types ofsorbents used to extract phenols using solid phase extraction (SPE);however, they are limited to mostly non-polar phenols, especially C₁₈.See I. Rodriguez, R. Cela, Combination of solid-phase extractionprocedures with gas chromatographic hyphenated techniques forchlorophenol determination in drinking water, TrAC—Trends Anal. Chem. 16(1997) 463-474, incorporated herein by reference in its entirety.SBA-15, a silica based mesoporous material, is known to be anoutstanding material for the trapping of different kinds of analytes invarious solution matrices. The excellent sorption abilities are due toits exceptional mechanical, thermal and chemical stabilities, inaddition to its large surface area and porosity. Moreover, SBA-15 isextremely inexpensive and simply obtained. Modification of SBA-15through functionalization or metal loading has shown significantimprovement in various applications including 1) heterogeneouscatalysis, 2) enzymatic immobilization such as encapsulation, 3)sensing, 4) drug delivery, and 5) adsorption studies. See S. A. Ganiyu,S. A. Ali, K. Alhooshani, Synthesis of a Ti-SBA-15-NiMohydrodesulfurization catalyst: the effect of the hydrothermal synthesistemperature of NiMo and molybdenum loading on the catalytic activity,Ind. Eng. Chem. Res. 56 (2017) 5201-5209; C. Rother, B. Nidetzky, Enzymeimmobilization by microencapsulation: methods, materials, andtechnological applications, in: Encycl. Ind. Biotechnol., John Wiley &Sons, Inc., Hoboken, NJ, USA, 2014: pp. 1-21; Y. Zhu, Z. Cheng, Q.Xiang, Y. Zhu, J. Xu, Rational design and synthesis ofaldehyde-functionalized mesoporous SBA-15 for high-performance ammoniasensor, Sensors Actuators, B Chem. 256 (2018) 888-895; T. Azaïs, G.Laurent, K. Panesar, A. Nossov, F. Guenneau, C. Sanfeliu Cano, C.Tourné-Péteilh, J.-M. Devoisselle, F. Babonneau, Implication of watermolecules at the silica-ibuprofen interface in silica-based drugdelivery systems obtained through incipient wetness impregnation, J.Phys. Chem. C. 121 (2017) 26833-26839; and M. Jahandar Lashaki, A.Sayari, CO₂ capture using triamine-grafted SBA-15: The impact of thesupport pore structure, Chem. Eng. J. 334 (2018) 1260-1269, eachincorporated herein by reference in their entirety. Organic functionalgroups have been immobilized within the framework of SBA-15 via variousapproaches for the adsorption of different analytes. By the two-steppost-grafting method, Junning et al. successfully attached imidazolegroups to mesoporous SBA-15 and used it for the extraction of hexavalentchromium from aqueous solution. See J. Li, T. Qi, L. Wang, C. Liu, Y.Zhang, Synthesis and characterization of imidazole-functionalized SBA-15as an adsorbent of hexavalent chromium, Mater. Lett. 61 (2007)3197-3200, incorporated herein by reference in its entirety. Variousaminosilanes have also been inserted on the framework of SBA-15. Theformed adsorbents were used in the adsorption of CO₂ both in thepresence and in the absence of water vapor. The surface density ofamines played a significant role in these adsorption studies. See N.Hiyoshi, K. Yogo, T. Yashima, Adsorption characteristics of carbondioxide on organically functionalized SBA-15, Microporous MesoporousMater. 84 (2005) 357-365, incorporated herein by reference in itsentirety. In a study to effectively separate bovine serum albuminprotein, 3-amino-propyltriethyoxysilane was attached to SBA-15 via apost-synthesis method. See T. P. B. Nguyen, J.-W. Lee, W. G. Shim, H.Moon, Synthesis of functionalized SBA-15 with ordered large pore sizeand its adsorption properties of BSA, Microporous Mesoporous Mater. 110(2008) 560-569, incorporated herein by reference in its entirety.Propylthiols have also been grafted to SBA-15 and were used for sizeselective adsorption of proteins in another study. See H. H. P. Yiu, C.H. Botting, N. P. Botting, P. A. Wright, Size selective proteinadsorption on thiol-functionalised SBA-15 mesoporous molecular sieve,Phys. Chem. Chem. Phys. 3 (2001) 2983-2985, incorporated herein byreference in its entirety.

Specifically, silica-based sorbents have been utilized in extractingphenolic compounds. Xiaoli et al. reported the application ofsurfactant-modified silica-magnetite nanoparticle-mixed hemimicelle forthe removal of phenols by solid phase extraction from water samples. SeeC. Shalaby, X. Ma, A. Zhou, C. Song, Preparation of organic sulfuradsorbent from coal for adsorption of dibenzothiophene-type compounds indiesel fuel, Energy and Fuels. 23 (2009) 2620-2627, incorporated hereinby reference in its entirety. By solid-phase microextraction method,silica fibers bonded to multiwalled carbon nanotubes performedremarkably in the removal of phenols in water samples. See H. Liu, J.Li, X. Liu, S. Jiang, A novel multiwalled carbon nanotubes bondedfused-silica fiber for solid phase microextraction-gas chromatographicanalysis of phenols in water samples, Talanta. 78 (2009) 929-935,incorporated herein by reference in its entirety. β-cyclodextrin bondedto silica has also been utilized in the extraction of phenols. See H.Faraji, β-Cyclodextrin-bonded silica particles as the solid-phaseextraction medium for the determination of phenol compounds in watersamples followed by gas chromatography with flame ionization and massspectrometry detection, J. Chromatogr. A. 1087 (2005) 283-288; Y. Fan,Y. Q. Feng, S. L. Da, On-line selective solid-phase extraction of4-nitrophenol with β-cyclodextrin bonded silica, Anal. Chim. Acta. 484(2003) 145-153; and Y. Hu, Y. Zheng, F. Zhu, G. Li, Sol-gel coatedpolydimethylsiloxane/beta-cyclodextrin as novel stationary phase forstir bar sorptive extraction and its application to analysis ofestrogens and bisphenol A, J. Chromatogr. A. 1148 (2007) 16-22, eachincorporated herein by reference in their entirety.

Instead of preparing hybrid materials based on silica as reported above,one purpose of the present disclosure is the direct functionalization ofSBA-15 with relatively polar groups such as 1,2,3-triazole and non-polargroups such as a long chain aliphatic group. The formed SBA-15functionalized sorbent will thus have the blend of both polar andnon-polar active sites.

A strategy based on the click reaction of azide functionalized SBA-15with phenylacetylene was used to develop a new sorbent(4-phenyl-1,2,3-triazole functionalized SBA-15) that has the property ofextracting both polar groups (due to the 1,2,3-triazole group) andmoderately polar groups (due to the presence of long straight chainalkyl group). See H. C. Kolb, M. G. Finn, K. B. Sharpless, Clickchemistry: diverse chemical function from a few good reactions, Angew.Chemie Int. Ed. 40 (2001) 2004-2021, incorporated herein by reference inits entirety. The sorbent was used in stir bar-supportedmicro-solid-phase extraction (SB-μ-SPE) of both highly polar(2,4-dichlorophenol (24DCP); 2,3-dichlorophenol (23DCP);2,6-dichlorophenol (26DCP); 2,4,6-trichlorophenol (246TCP)) andmoderately polar (2,6-di-tert-butyl-4-m ethyl phenol (26DTB4MP);4-tert-octylphenol (4tOP); 2-benzyl-4-chlorophenol (2B4CP)) phenols.

The SB-μ-SPE extraction method is an improvement of themicro-solid-phase extraction (μ-SPE). See C. Basheer, A. A. Alnedhary,B. S. M. Rao, S. Valliyaveettil, H. K. Lee, Development and applicationof porous membrane-protected carbon nanotube micro-solid-phaseextraction combined with gas chromatography/mass spectrometry., Anal.Chem. 78 (2006) 2853-8; and M. Sajid, Porous membrane protectedmicro-solid-phase extraction: A review of features, advancements andapplications, Anal. Chim. Acta. In Press, (2017), each incorporatedherein by reference in their entirety. In this method, a tiny stir-baris inserted inside a polypropylene (PP) membrane together with thesorbent and then sealed with a heater. The tiny stir-bar helps to solvethe issue of floating of the PP membrane over sample solution orclinging to the side of the sample vial. In addition, it also enhancedthe interaction of PP membrane and sample solution through continuousstirring and rotation, which in turn increases the effective surfacearea of the sorbent provided to the analytes in the sample solution. SeeM. Sajid, C. Basheer, M. Daud, A. Alsharaa, Evaluation of layered doublehydroxide/graphene hybrid as a sorbent in membrane-protected stir-barsupported micro-solid-phase extraction for determination oforganochlorine pesticides in urine samples, J. Chromatogr. A. 1489(2017) 1-8; and M. Sajid, C. Basheer, Stir-bar supportedmicro-solid-phase extraction for the determination of polychlorinatedbiphenyl congeners in serum samples, J. Chromatogr. A. 1455 (2016)37-44, each incorporated herein by reference in their entirety.

In view of the foregoing, one objective of the present invention is toprovide a functionalized silica sorbent made of porous silicananoparticles having a surface functionalized with a conjugated systemattached by an alkyl chain of length C₈-C₁₆ and a method of using thesorbent to adsorb phenolic materials from solution.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect, the present disclosure relates to afunctionalized silica sorbent made of porous silica nanoparticles havinga surface functionalized with a conjugated system attached by an alkylchain of length C₈-C₁₆. The porous silica nanoparticles have an averageparticle size of 10-80 nm, and the conjugated system comprises an azolegroup and a phenyl group.

In one embodiment, the porous silica nanoparticles are clustered inagglomerates having an average diameter of 1-4 μm.

In one embodiment, the porous silica nanoparticles have an average poresize in a range of 4-9 nm.

In one embodiment, the porous silica nanoparticles have a BET surfacearea of 200-380 m²/g.

In one embodiment, the porous silica nanoparticles have a total porevolume in a range of 0.380-0.700 cm³/g.

In one embodiment, the conjugated system consists of a triazole groupand a phenyl group.

In one embodiment, the conjugated system is 4-phenyl-1,2,3-triazole.

In one embodiment, the alkyl chain has a length of C₁₀-C₁₂.

In one embodiment, the functionalized silica sorbent has 3-12 wt % Nrelative to a total weight of the functionalized silica sorbent.

In one embodiment, the functionalized silica sorbent has 50-58 wt % Sirelative to a total weight of the functionalized silica sorbent.

According to a second aspect, the present disclosure relates to a methodfor producing the functionalized silica sorbent of the first aspect.This involves mixing a silicon alkoxide, an azidoalkyltrialkoxysilane,and a structure directing agent with an acidic solution to produce areaction mixture. The reaction mixture is heated in an autoclave at80-120° C. for 18-30 h to produce an azide-functionalized silica. Theazide-functionalized silica is mixed with an aqueous solution, a coppersalt, and an arylalkyne for 4-24 h to produce the functionalized silicasorbent.

In one embodiment, the azidoalkyltrialkoxysilane isazidoundecyltrimethoxysilane.

In one embodiment, the silicon alkoxide is tetraethyl orthosilicate.

In one embodiment, the structure directing agent is a nonionic blockcopolymer.

In one embodiment, the copper salt is CuSO₄.

According to a third aspect, the present disclosure relates to a methodof adsorbing a contaminant from an aqueous solution. This methodinvolves mixing the functionalized silica sorbent of the first aspect inthe aqueous solution comprising the contaminant at a concentration of1-600 ng/mL, where a concentration of the functionalized silica sorbentafter mixing is 1-100 mg/mL. At least 85 wt % of the contaminant isadsorbed by the functionalized silica sorbent in 10-25 min relative to atotal weight of the contaminant.

In one embodiment, the contaminant is at least one selected from thegroup consisting of a dichlorophenol, a trichlorophenol,2,6-di-tert-butyl-4-methylphenol, 4-tert-octylphenol, and abenzyl-chlorophenol.

In one embodiment, the functionalized silica sorbent is confined withina porous membrane bag.

In one embodiment, the aqueous solution further comprises an inorganicsalt at a concentration of 0.01-0.2 g/mL.

In one embodiment, the method also involves desorbing the contaminant bysonicating the functionalized silica sorbent in an organic solvent for15-30 min.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 illustrates the step-by-step synthesis of 4-phenyl-1,2,3-triazolefunctionalized SBA-15.

FIG. 2A shows the 400 MHz proton MAS NMR spectrum of4-phenyl-1,2,3-triazole functionalized SBA-15 at ambient temperature.

FIG. 2B shows the ¹³C CP MAS NMR spectrum of 4-phenyl-1,2,3-triazolefunctionalized SBA-15 at ambient temperature.

FIG. 3A is the N₂-adsorption desorption isotherm of the xN₃-SBA-15adsorbents showing a type IV isotherm.

FIG. 3B is the N₂-adsorption desorption isotherm of the xN₃-Ph-SBA-15adsorbents showing a type IV isotherm.

FIG. 4A is an FESEM of the 2N₃-SBA-15 adsorbent.

FIG. 4B is an FESEM of the 5N₃-SBA-15 adsorbent.

FIG. 4C is an FESEM of the 10N₃-SBA-15 adsorbent.

FIG. 4D is an FESEM of the 2N₃-Ph-SBA-15 adsorbent.

FIG. 4E is an FESEM of the 5N₃-Ph-SBA-15 adsorbent.

FIG. 4F is an FESEM of the 10N₃-Ph-SBA-15 adsorbent.

FIG. 5A shows the FTIR spectra of the xN₃-SBA-15 and the SBA-15adsorbents.

FIG. 5B shows the FTIR spectra of the xN₃-Ph-SBA-15 adsorbents.

FIG. 6 shows a comparison of sorbent material varied by4-phenyl-1,2,3-triazole weight %. Conditions: phenol mix concentration:200 ng mL⁻¹: sorbent mass: 30 mg; extraction time: 20 min; desorptionsolvent: methanol; desorption volume: 200 μL; desorption time: 10 min;salt mass: 1.0 g.

FIG. 7 is a graph illustrating the effect of different sorbent mass:Conditions: phenol mix concentration: 200 ng mL⁻; sorbent material:10N₃-Ph-SBA-15; extraction time: 20 min; desorption solvent: methanol;desorption volume: 200 μL; desorption time: 10 min; salt mass: 1.0 g.

FIG. 8 is a graph illustrating the effect of different types ofdesorption solvent: Conditions: phenol mix concentration: 200 ng mL⁻¹;sorbent material: 10N₃-Ph-SBA-15; sorbent mass: 20 mg; extraction time:20 min; desorption volume: 200 μL; desorption time: 10 min; salt mass:1.0 g;

FIG. 9 is a graph illustrating the effect of different desorptionsolvent volumes: Conditions: phenol mix concentration: 200 ng mL⁻¹;sorbent material: 10N₃-Ph-SBA-15; sorbent mass: 20 mg; extraction time:20 min; desorption solvent: ethyl acetate; desorption time: 10 min; saltmass: 1.0 g.

FIG. 10 is a graph illustrating the effect of salt addition: Conditions:phenol mix concentration: 200 ng mL⁻¹; sorbent material: 10N₃-Ph-SBA-15;sorbent mass: 20 mg; extraction time: 20 min; desorption solvent: ethylacetate; desorption volume: 300 μL; desorption time: 10 min;

FIG. 11 is a graph illustrating the effect of different extractiontimes: Conditions: phenol mix concentration: 200 ng mL⁻¹; sorbentmaterial: 10N₃-Ph-SBA-15; sorbent mass: 20 mg; desorption solvent: ethylacetate; desorption volume: 300 μL; desorption time: 10 min; salt mass:0.5 g.

FIG. 12 is a graph illustrating the effect of different desorptiontimes: Conditions: phenol mix concentration: 200 ng mL⁻¹; sorbentmaterial: 10N₃-Ph-SBA-15; sorbent mass: 20 mg; extraction time: 15 min;desorption solvent: ethyl acetate; desorption volume: 300 μL; salt mass:0.5 g.

FIG. 13 illustrates GC-MS overlaid chromatograms of unspiked wastewaterand wastewater spiked with 1 ng mL⁻¹ of the phenols mixture.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the present disclosure will now be described more fullyhereinafter with reference to the accompanying drawings, in which some,but not all embodiments of the disclosure are shown.

The present disclosure will be better understood with reference to thefollowing definitions. As used herein, the words “a” and “an” and thelike carry the meaning of “one or more.” Within the description of thisdisclosure, where a numerical limit or range is stated, the endpointsare included unless stated otherwise. It will be further understood thatthe terms “comprises” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

As used herein, the words “about,” “approximately,” or “substantiallysimilar” may be used when describing magnitude and/or position toindicate that the value and/or position described is within a reasonableexpected range of values and/or positions. For example, a numeric valuemay have a value that is +/− 0.1% of the stated value (or range ofvalues), +/− 1% of the stated value (or range of values), +/− 2% of thestated value (or range of values), +/− 5% of the stated value (or rangeof values), +/− 10% of the stated value (or range of values), +/− 15% ofthe stated value (or range of values), or +/− 20% of the stated value(or range of values). Within the description of this disclosure, where anumerical limit or range is stated, the endpoints are included unlessstated otherwise. Also, all values and subranges within a numericallimit or range are specifically included as if explicitly written out.

As used herein, “compound” is intended to refer to a chemical entity,whether as a solid, liquid, or gas, and whether in a crude mixture orisolated and purified.

As used herein, “composite” refers to a combination of two or moredistinct constituent materials into one. The individual components, onan atomic level, remain separate and distinct within the finishedstructure. The materials may have different physical or chemicalproperties, that when combined, produce a material with characteristicsdifferent from the original components. In some embodiments, a compositemay have at least two constituent materials that comprise the sameempirical formula but are distinguished by different densities, crystalphases, or a lack of a crystal phase (i.e. an amorphous phase).

The present disclosure is intended to include all hydration states of agiven compound or formula, unless otherwise noted or when heating amaterial. For example, Ni(NO₃)₂ includes anhydrous Ni(NO₃)₂,Ni(NO₃)₂·6H₂O, and any other hydrated forms or mixtures. CuCl₂ includesboth anhydrous CuCl₂ and CuCl₂·2H₂O.

In addition, the present disclosure is intended to include all isotopesof atoms occurring in the present compounds and complexes. Isotopesinclude those atoms having the same atomic number but different massnumbers. By way of general example, and without limitation, isotopes ofhydrogen include deuterium and tritium. Isotopes of carbon include ¹³Cand ¹⁴C. Isotopes of nitrogen include ¹⁴N and ¹⁵N. Isotopes of oxygeninclude ¹⁶O, ¹⁷O, and ¹⁸O. Isotopes of silicon include ²⁸Si, ²⁹Si, ³⁰Si,³¹Si, and ³²Si. Isotopically-labeled compounds of the disclosure maygenerally be prepared by conventional techniques known to those skilledin the art or by processes analogous to those described herein, using anappropriate isotopically-labeled reagent in place of the non-labeledreagent otherwise employed.

According to a first aspect, the present disclosure relates to afunctionalized silica sorbent made of porous silica nanoparticles havinga surface functionalized with a conjugated system attached by an alkylchain of length C₈-C₁₆. As defined here, a “sorbent” is a material usedto absorb and/or adsorb one or more compounds. Throughout thisdisclosure the terms “absorbing a contaminant” and “adsorbing acontaminant” are taken to have equivalent meanings. Additionally,“sorbent” is taken to have the same meaning as “adsorbent” and“absorbent.”

In one embodiment, the porous silica nanoparticles have an averageparticle size of 10-80 nm, 15-50 nm, 18-30 nm, preferably 20-28 nm, morepreferably 21-27 nm, or about 23 nm, though in some embodiments, theaverage particle size may be less than 10 nm or greater than 80 nm.

The porous silica nanoparticles may have a spherical shape, or may beshaped like cylinders, boxes, spikes, flakes, plates, ellipsoids,toroids, stars, ribbons, discs, rods, granules, prisms, cones, flakes,platelets, sheets, or some other shape. In one embodiment, the poroussilica nanoparticles may be substantially spherical, meaning that thedistance from the particle centroid (center of mass) to anywhere on thenanoparticle outer surface varies by less than 30%, preferably by lessthan 20%, more preferably by less than 10% of the average di stance.

In one embodiment, the porous silica nanoparticles are monodisperse,having a coefficient of variation or relative standard deviation,expressed as a percentage and defined as the ratio of the particlediameter standard deviation (σ) to the particle diameter mean (μ),multiplied by 100%, of less than 25%, preferably less than 10%,preferably less than 8%, preferably less than 6%, preferably less than5%. In a preferred embodiment, the porous silica nanoparticles aremonodisperse having a particle diameter distribution ranging from 80% ofthe average particle diameter to 120% of the average particle diameter,preferably 85-115%, preferably 90-110% of the average particle diameter.In another embodiment, the porous silica nanoparticles are notmonodisperse

In one embodiment, the porous silica nanoparticles are clustered inagglomerates having an average diameter of 1-4 μm, preferably 1.5-3.8μm, more preferably 2.0-3.5 μm, even more preferably about 3 μm. As usedherein, the term “agglomerates” refers to a clustered particulatecomposition comprising primary particles, the primary particles beingaggregated together in such a way so as to form clusters thereof, atleast 50 volume percent of the clusters having a mean diameter that isat least 2 times the mean diameter of the primary particles, andpreferably at least 90 volume percent of the clusters having a meandiameter that is at least 5 times the mean diameter of the primaryparticles. In this embodiment, the primary particles are the poroussilica nanoparticles having a mean diameter as previously described.

In one embodiment, the porous silica nanoparticles have an average poresize in a range of 4-9 nm, preferably 5-8 nm, more preferably 6-7 nm,even more preferably about 6.5 nm. However, in some embodiments, theaverage pore size may be smaller than 4 nm or greater than 9 nm. In oneembodiment, the porous silica nanoparticles may be considered mesoporoussilica, meaning that the pores have diameters between 2 and 50 nm. In afurther embodiment, the porous silica nanoparticles may comprise poresin a hexagonal arrangement. In another further embodiment, the poroussilica nanoparticles may be called SBA-15, or functionalized SBA-15. Inone embodiment, the porous silica nanoparticles may comprise 60-100 wt %silica, preferably 70-95 wt % silica, relative to a total weight of theporous silica nanoparticles.

In one embodiment, the porous silica nanoparticles have a BET surfacearea in a range of 200-380 m²/g, preferably 220-330 m²/g, morepreferably 230-300 m²/g, even more preferably 250-260 m²/g. Inalternative embodiments, the porous silica nanoparticles may have a BETsurface area of less than 200 m²/g or greater than 380 m²/g.

In one embodiment, the porous silica nanoparticles have a total porevolume in a range of 0.380-0.700 cm³/g, preferably 0.390-0.600 cm³/g,more preferably 0.400-0.500 cm³/g, though in some embodiments, theporous silica nanoparticles may have a total pore volume of less than0.380 cm³/g or greater than 0.700 cm³/g.

The surface of the porous silica nanoparticles is functionalized with aconjugated system attached by an alkyl chain of length C₈-C₁₆,preferably C₉-C₁₄, more preferably C₁₀-C₁₂. In one embodiment, thesurface is functionalized with a conjugated system attached by an alkylchain length of C₁₁ (i.e. 11 carbons). As defined here, the surfacebeing functionalized with a conjugated system means that the surface,the alkyl chain, and the conjugated system are all connected throughcovalent bonds, and the “surface” includes interior surfaces withinpores.

As used herein, the term “alkyl” unless otherwise specified, refers toboth branched and straight chain saturated aliphatic primary, secondary,and/or tertiary hydrocarbons of typically C₁ to C₁₆, and specificallyincludes, but is not limited to, methyl, trifluoromethyl, ethyl, propyl,isopropyl, cyclopropyl, butyl, isobutyl, t-butyl, pentyl, cyclopentyl,isopentyl, neopentyl, hexyl, isohexyl, cyclohexyl, cyclohexylmethyl,3-methylpentyl, 2,2-dimethylbutyl, and 2,3-dimethylbutyl. As usedherein, the term may also include substituted alkyl groups. Exemplarymoieties with which the alkyl group can be substituted may be selectedfrom the group including, but not limited to, hydroxyl, amino,alkylamino, arylamino, alkoxy, aryloxy, nitro, cyano, sulfonic acid,sulfate, phosphonic acid, phosphate, or phosphonate or mixtures thereof.In a preferred embodiment, the conjugated system is attached by an alkylchain comprising a straight chain of saturated aliphatic secondaryhydrocarbons.

As defined here, the conjugated system refers to a system of connected porbitals with delocalized electrons in a molecule. A conjugated systemis conventionally represented as having alternating single and multiplebonds and may be cyclic, acyclic, linear, or mixed. A conjugated systemmay also comprise electron lone pairs, radicals, or carbenium ions. Inone embodiment, the conjugated system comprises one or more aromaticcyclic compounds. In one embodiment, the conjugated system comprises twoaromatic cyclic compounds.

In one embodiment, the conjugated system may comprise 1,2,3-triazine,1,2,4-triazine, 1,3,5-triazine (s-triazine), acridine, annulene,anthracene, azole, benzene, benzimidazole, benzisoxazole,benzo[c]thiophene, benzofuran, benzothiazole, benzothiophene,benzoxazole, cinnoline, furan, imidazole, indazole, indole,isobenzofuran, isoindole, isoquinoline, isoxazole, naphthalene, oxazole,phenanthrene, phenyl, phthalazine, purine, pyrazine, pyrazole,pyridazine, pyridine, pyrimidine, pyrrole, quinazoline, quinoline,quinoxaline, thiazole, thiophene, or some other aromatic group.Preferably the conjugated system comprises an azole group and phenylgroup. In one embodiment, the conjugated system consists of an azolegroup and a phenyl group. In a preferred embodiment, the conjugatedsystem consists of a triazole group and a phenyl group, and in a morepreferred embodiment, the conjugated system is 4-phenyl-1,2,3-triazole.

In one embodiment, the functionalized silica sorbent comprises N at aweight percentage of 3-12 wt %, preferably 4-11 wt %, more preferably5-10 wt %, even more preferably 6-9 wt % relative to a total weight ofthe functionalized silica sorbent. However, in some alternativeembodiments, the functionalized silica sorbent comprises less than 3 wt% or greater than 12 wt % N relative to a total weight of thefunctionalized silica sorbent.

In one embodiment, the functionalized silica sorbent comprises Si at aweight percentage of 50-58 wt %, preferably 51-56 wt %, more preferably52-55 wt % relative to a total weight of the functionalized silicasorbent. However, in some alternative embodiments, the functionalizedsilica sorbent may comprise less than 50 wt % or greater than 58 wt % Sirelative to a total weight of the functionalized silica sorbent.

In one embodiment, the functionalized silica sorbent comprises 0(oxygen) at a weight percentage of 34-45 wt %, preferably 35-41 wt %,more preferably 36-40 wt %, relative to a total weight of thefunctionalized silica sorbent. However, in some alternative embodiments,the functionalized silica sorbent may comprise less than 34 wt % orgreater than 45 wt % O relative to a total weight of the functionalizedsilica sorbent.

According to a second aspect, the present disclosure relates to a methodfor producing the functionalized silica sorbent of the first aspect.This involves mixing a silicon alkoxide, an azidoalkyltrialkoxysilane,and a structure directing agent with an acidic solution to produce areaction mixture. The reaction mixture is heated in an autoclave toproduce an azide-functionalized silica. The azide-functionalized silicais mixed with an aqueous solution, a copper salt, and an arylalkyne toproduce the functionalized silica sorbent.

In one embodiment, the structure directing agent is a nonionic blockcopolymer. A block copolymer is a specific type of copolymer made up ofblocks of different polymerized monomers. In a block copolymer, aportion of the macromolecule comprising many constitutional units has atleast one feature which is not present in the adjacent portions. Blockcopolymers comprise two or more homopolymer subunits linked by covalentbonds. The union of the homopolymer subunits may require an intermediatenon-repeating subunit, known as a junction block. Block copolymers withtwo or three distinct blocks are called diblock copolymers and triblockcopolymers respectively, tetrablocks, and multiblocks, etc. may also befabricated. In stereoblock copolymers, a special structure may be formedfrom one monomer where the distinguishing feature is the tacticity ofeach block. The structure directing agent may be a block copolymer, astereoblock copolymer, or mixtures thereof.

In one embodiment, the structure directing agent is a poloxamer.Poloxamers are nonionic triblock copolymers composed of a centralhydrophobic chain of polyoxypropylene (poly(propylene oxide), or PPO)flanked by two hydrophilic chains of polyoxyethylene (poly(ethyleneoxide), or PEO). Because the lengths of the polymer blocks may becustomized, many different poloxamers exist that have slightly differentproperties. For the generic term poloxamer, these copolymers arecommonly named with the letter P (for poloxamer) followed by threedigits: the first two digits multiplied by 100 give the approximatemolecular mass of the polyoxypropylene core in g/mol, and the last digitmultiplied by 10 gives the percentage polyoxyethylene content. In oneembodiment, the structure directing agent is P123 poloxamer, which is asymmetric triblock copolymer comprising poly(ethylene oxide) (PEO) andpoly(propylene oxide) (PPO) in an alternating linear fashion,PEO-PPO-PEO. The unique characteristic of PPO block, which ishydrophobic at temperatures above 288 K and is soluble in water attemperatures below 288 K, leads to the formation of micelles comprisingPEO-PPO-PEO triblock copolymers. The nominal chemical formula of P123 isHO(CH₂CH₂O)₂₀(CH₂CH(CH₃)O)₇₀(CH₂CH₂O)₂₀H, which corresponds to amolecular weight of around 5,800 g/mol. P123 poloxamer may be known bythe trade name Pluronic® P-123.

In one embodiment, the azidoalkyltrialkoxysilane is anazidoalkyltrimethoxysilane or an azidoalkyltriethoxysilane, though insome embodiments, a mixture of azidoalkyltrimethoxysilanes andazidoalkyltriethoxysilanes may be used. Preferably theazidoalkyltrialkoxysilane is an azidoalkyltrimethoxysilane. In oneembodiment, the azidoalkyltrimethoxysilane may beazidomethyltrimethoxysilane, azidoethyltrimethoxysilane,azidopropyltrimethoxysilane, azidobutyltrimethoxysilane,azidopentyltrimethoxysilane, azidohexyltrimethoxysilane,azidoheptyltrimethoxysilane, azidooctyltrimethoxysilane,azidononyltrimethoxysilane, azidodecyltrimethoxysilane,azidoundecyltrimethoxysilane, azidododecyltrimethoxysilane,azidomethyltriethoxysilane, azidoethyltriethoxysilane,azidopropyltriethoxysilane, azidobutyltriethoxysilane,azidopentyltriethoxysilane, azidohexyltriethoxysilane,azidoheptyltriethoxysilane, azidooctyltriethoxysilane,azidononyltriethoxysilane, azidodecyltriethoxysilane,azidoundecyltriethoxysilane, and/or azidododecyltriethoxysilane. In apreferred embodiment, the azidoalkyltrialkoxysilane isazidoundecyltrimethoxysilane.

In one embodiment, the silicon alkoxide is tetraethyl orthosilicate,tetramethyl orthosilicate, tetrapropyl orthosilicate, and/or tetrabutylorthosilicate. In a preferred embodiment, the silicon alkoxide istetraethyl orthosilicate (TEOS).

The silicon alkoxide, azidoalkyltrialkoxysilane, and structure directingagent are mixed with an acidic solution to produce a reaction mixture.The acidic solution may comprise 9-17 wt %, preferably 10-16 wt %, morepreferably 11-15 wt % acid relative to the total weight of the acidicsolution, with the remaining weight percentage comprising water,preferably deionized or distilled water. The acid may be formic acid,benzoic acid, acetic acid, phosphoric acid, hydrobromic acid, hydroiodicacid, nitric acid, hydrochloric acid, hydrofluoric acid, sulfuric acid,and/or perchloric acid or some other acid. Preferably the acid is nitricacid, hydrochloric acid, hydrofluoric acid, sulfuric acid, and/orperchloric acid; more preferably the acid is hydrochloric acid. Thereaction mixture may comprise the acidic solution at a weight percentageof 85-97 wt %, preferably 87-95 wt %, more preferably 89-94 wt %,relative to a total weight of the reaction mixture. The reaction mixturemay comprise the structure directing agent at a weight percentage of0.5-5.0 wt %, preferably 1.0-4.5 wt %, relative to a total weight of thereaction mixture. The silicon alkoxide and the azidoalkyltrialkoxysilanemay have a combined weight that is 3-8 wt %, preferably 4-7 wt % of thetotal weight of the reaction mixture. More specifically, theazidoalkyltrialkoxysilane may be present in the reaction mixture at aweight percentage of 1-15 wt %, preferably 2-12 wt % relative to a totalweight of the reaction mixture, or about 2 wt %, or about 5 wt %, ormore preferably about 10 wt %.

Prior to any heating, the reaction mixture may be stirred for 1-48 h,preferably 6-24 h, more preferably 12-20 h. In one embodiment, thereaction mixture is heated in an autoclave at 80-120° C., preferably82-110° C., more preferably 85-100° C., or about 90° C. for 18-30 h,preferably 20-28 h, more preferably 22-26 h to produce anazide-functionalized silica, by means of a condensation reaction betweenthe silicon alkoxide and the azidoalkyltrialkoxysilane. Theazide-functionalized silica may be in the form of mesoporousnanoparticles. The azide-functionalized silica may be dried, forinstance, in an oven at 80-120° C., preferably 85-105° C., for 3-24 h,preferably 6-18 h, or 8-12 h. In one embodiment, to remove the structuredirecting agent, the dried azide-functionalized silica may be sonicatedor mixed in a solvent comprising water, methanol, ethanol, and/orisopropanol for 2-10 h, preferably 4-8 h, and then removed and dried at80-120° C., preferably 85-105° C., for 3-24 h, preferably 12-20 h.

The azide-functionalized silica is mixed with an aqueous solution, acopper salt, and an arylalkyne to produce the functionalized silicasorbent. The aqueous solution, copper salt, and arylalkyne may be addedtogether and mixed for 6-24 h, preferably 8-22 h, more preferably 12-20h, or overnight. In one embodiment, the aqueous solution comprises 30-70vol % of an alcohol, preferably 40-60 vol %, more preferably about 50vol %, and 30-70 vol % of water, preferably 40-60 vol % water, morepreferably about 50 vol %, relative to a total volume of the aqueoussolution. In one embodiment, the aqueous solution further comprises areducing agent, such as sodium ascorbate, some other ascorbate salt,sodium citrate, sodium borohydride, sodium hypophosphite, or hydrazine,or some other reducing agent. The reducing agent may be present at aweight percentage of 0.001-0.01 wt %, 0.01-0.05 wt %, 0.05-0.1 wt %,0.1-10 wt %, 0.5-8 wt %, 0.8-5 wt %, 1.0-4.5 wt %, or 1.5-4.0 wt %,relative to a total weight of the aqueous solution.

The copper salt and the arylalkyne may be added to an amount thatapproximates or is a 1:1 molar ratio with the number of azide groups inthe azide-functionalized silica. For instance, an amount of the coppersalt may be added so that a molar ratio of the copper salt to the azidegroups is in a range of 1:1.1-1.1:1, preferably 1:1.05-1.05:1. An amountof the arylalkyne added may have a molar ratio with azide groups in arange of 1:1.1-1.1:1, preferably 1:1.05-1.05:1.

In one embodiment, the copper salt may be Cu(BF₄)₂, CuBr₂, CuC₂, CuCO₃,Cu(CN)₂, Cu(ClO₃)₂, CuCl₂, CuF₂, Cu(NO₃)₂, Cu₃(PO₄)₂, CuN₆, CuO, CUO₂,Cu(OH)₂, CuI₂, CuS, CuSO₄, Cu₃(AsO₄)₂, CuBr, CuCN, CuCl, CuF, CuH, CuI,Cu₂C₂, Cu₂Cr₂O₅, Cu₂O, CuOH, CuNO₃, Cu₃P, Cu₂S, CuSCN, and/or Cu₃H₄O₈S₂.Preferably, the copper salt is CuSO₄.

In one embodiment, the arylalkyne may be phenyl acetylene, tolylacetylene, xylyl acetylene, or naphthyl acetylene.

In one embodiment, the mixing of the azide-functionalized silica withthe other components forms the functionalized silica sorbent by a Cucatalyzed click reaction. More specifically, this may be known as anazide-alkyne Huisgen cycloaddition, which is a 1,3-dipolar cycloadditionbetween an azide and a terminal or internal alkyne to give a1,2,3-triazole. The formed functionalized silica sorbent may be washedwith methanol, ethanol, isopropanol, or water to remove remaining coppercompounds.

According to a third aspect, the present disclosure relates to a methodof adsorbing a contaminant from an aqueous solution. This methodinvolves mixing the functionalized silica sorbent of the first aspect inthe aqueous solution. After the mixing, the functionalized silicasorbent may be present in the aqueous solution at a mass to volume ratio(mass sorbent to volume aqueous solution) of 1-100 mg/mL, preferably2-80 mg/mL, more preferably 10-50 mg/mL, even more preferably 20-30mg/mL. In some embodiments, prior to mixing the functionalized silicasorbent with the aqueous solution, the functionalized silica sorbent maybe conditioned by sonicating in an organic solvent, such as toluene orchloroform, for a period of 1-15 min, preferably 3-10 min.

In one embodiment, the aqueous solution may come from a body of watersuch as an ocean, a bay, a river, a spring, a lake, a swamp, or a pondor alternatively, from a treated artificial body of water, such as apool, fountain, bath, aquarium, or hot tub. The sample may also be watertaken from other natural environments such as groundwater (such as awell or an aquifer), rainwater, dew, fog, hot spring, a steam vent,snow, ice, or a geyser. In other embodiments, the aqueous solution maycome from processed water or wastewater of industrial process includingbut not limited to a water treatment plant, a sewage treatment plant, adesalination plant, a manufacturing plant, a chemical plant, a textileplant, a power plant, a gas station, a food processing plant (such asmilk, fruit juice, or honey), a restaurant, a dry cleaner, or some otherplace that may be a source of contaminated water mixtures. In otherembodiments, the aqueous solution may be prepared in a laboratory orpilot plant for the purpose of testing removal of contaminants.

In an alternative embodiment, a contaminant may be confined within asolid sample, for instance, a sample of biological origin, such asvegetative matter, bacteria, or animal tissue. Here, a solid sample maybe processed in a solution in order to release the contaminant into theaqueous solution. This processing may lyse the cells of a biologicalsample, and may comprise sonication, microwaving, heating, extrusion,grinding, liquid homogenization, blending, scraping, slicing,centrifuging, drying, osmotic shock, and/or freeze-thawing.

The aqueous solution may comprise the contaminant at a concentration of1-600 ng/mL, preferably 100-500 ng/mL, more preferably 150-450 ng/mL. Inother embodiments, the contaminant may be present at a concentration ofless than 1 ng/mL or greater than 600 ng/mL.

In one embodiment, the contaminant may be an herbicide, a dye, afungicide, a pesticide, a drug, a steroid, a microbial toxin, ametabolite, a disinfection byproduct, a phenol compound, or some othersmall organic molecule. Disinfection byproducts may include iodoaceticacid, N-nitrosodimethylamine (NDMA), nitrogentrichloride, chloramine,halonitromethanes, haloacetonitriles, haloamides, halofuranones,nitrosamines, trihalomethanes, and haloketones. Phenol compounds includesalicylic acid, monochlorophenol, dichlorophenol, trichlorophenol,2,6-di-tert-butyl-4-methylphenol (26DTB4MP), 4-tert-octylphenol (4tOP),and benzyl-chlorophenol. More specifically, monochlorophenol includes2-chlorophenol, 3-chlorophenol, and 4-chlorophenol. Dichlorophenolincludes 2,4-dichlorophenol (24DCP), 2,3-dichlorophenol (23DCP),2,5-dichlorophenol (25DCP), 2,6-dichlorophenol (26DCP),3,4-dichlorophenol (34DCP), and 3,5-dichlorophenol (35DCP).Trichlorophenol includes 2,3,4-trichlorophenol (234TCP),2,3,5-trichlorophenol (235TCP), 2,3,6-trichlorophenol (236TCP),2,4,5-trichlorophenol (245TCP), 2,4,6-trichlorophenol (246TCP), and3,4,5-trichlorophenol (345TCP). Benzyl-chlorophenol includes2-benzyl-4-chlorophenol (2B4CP). The contaminant may be other phenolcompounds, such as other organohalides of phenol not previouslymentioned. Preferably the contaminant is one or more phenol compounds.

In one embodiment, the aqueous solution further comprises an inorganicsalt at a concentration of 0.01-0.2 g/mL, preferably 0.02-0.15 g/mL,more preferably 0.03-0.10 g/mL. In alternative embodiments, the aqueoussolution may comprise the inorganic salt at a concentration of less than0.05 g/mL or greater than 0.2 g/mL. The inorganic salt may be NaCl, KCl,LiCl, NaBr, KBr, LiBr, NaNO₃, KNO₃, LiNO₃, or some other inorganic salt.Preferably the inorganic salt is NaCl.

In one embodiment, the functionalized silica sorbent is confined withina porous membrane bag. A single porous membrane bag may confine In oneembodiment, the porous membrane of the porous membrane bag may comprisea polymer such as polypropylene, polyethylene, nylon, polyvinylidenefluoride, or polyethersulfone, preferably polypropylene or polyethylene,even more preferably polypropylene. In an alternative embodiment, morethan one polymer may comprise the porous membrane. For example, theporous membrane may be composed of both polypropylene and polyethylenewith a polypropylene to polyethylene weight ratio range of 1:10-10:1,preferably 1:5-5:1, more preferably 1:2-2:1.

In one embodiment, the porous membrane has a wall thickness of 10-400μm, preferably 50-300 μm, more preferably 100-200 μm. The porousmembrane may have a pore diameter of 0.04-0.80 μm, preferably 0.1-0.5μm, more preferably 0.1-0.4 μm. The membrane may have a porosity of40-90 vol %, preferably 50-85 vol %, more preferably 60-80 vol %. Theaqueous solution may fill 70-100%, preferably 80-100%, more preferably90-100% of the pores exposed to the aqueous solution from the interiorof the membrane bag. The porous membrane bag may comprise more than onepiece of membrane, for instance, the bag may comprise both an inner andouter membrane layer. Where the bag comprises more than one membrane,the membranes may be made of identical material. Alternatively, themembranes may be made of different material, have different thicknesses,and/or have different pore sizes.

The porous membrane bag may comprise a membrane in the shape of a tube,for example, a hollow fiber membrane, where the ends of the tube areclosed in order to contain the functionalized silica sorbent. The edgesmay be closed by an adhesive, a clamp, a tie, or by heat sealing.Alternatively, the membrane may form a balloon shape around thefunctionalized silica sorbent, with the membrane closed at one side, orwith the membrane edges tied at one point. Alternatively, the membranebag may form a rectangular pillow shape around the functionalized silicasorbent. In this embodiment, the four edges may be sealed along eachedge, or one edge may be a fold in the membrane with the remaining edgesbeing sealed along each edge. In this pillow shape, the edges maymeasure 1-5 cm, preferably 2-4 cm, more preferably 2.2-3 cm in length,and the height may be 0.4-5 cm, preferably 0.8-4 cm, more preferably0.8-2.8 cm.

In one embodiment, the porous membrane bag may also confine a magneticstir bar, for instance, a stir bar having a length of 4-10 mm,preferably 5-8 mm, and a width of 1-4 mm, preferably 1.2-2.5 mm. Inother embodiments, the porous membrane bag may be attached to a stringfor ease of handling. However, in alternative embodiments, thefunctionalized silica sorbent may not be confined within a porousmembrane bag, but instead may be removed from the aqueous solution byfiltering, or centrifuging and decanting. In one embodiment, during themixing, the aqueous solution may be kept at room temperature or heatedto 30-60° C., preferably 32-40° C., or the aqueous solution may becooled below room temperature, for instance, to 10-15° C.

Following mixing the functionalized silica sorbent in the aqueoussolution comprising the contaminant, at least 70 wt %, at least 75 wt %,at least 85 wt %, at least 90 wt %, or at least 95 wt % of thecontaminant, relative to a total weight of the contaminant, is adsorbedby the functionalized silica sorbent in a time period of 5-60 min,preferably 8-30 min, more preferably 10-25 min, even more preferably15-20 min, or about 15 min. Preferably, with or without a magnetic stirbar, the functionalized silica sorbent and the aqueous solution arestirred or agitated over that time period of adsorption. In someembodiments, the functionalized silica sorbent and aqueous solution maybe stirred or agitated much longer, for instance 10-24 h, or 12-18 h.The functionalized silica sorbent and aqueous solution may be stirred oragitated at a rate of 100-1,400 rpm, preferably 300-1,200 rpm.

In one embodiment, after the adsorbing, the functionalized silicasorbent (including a porous membrane bag, if present) is removed fromthe aqueous solution, rinsed with ethanol, methanol, and/or water, anddried at room temperature.

In one embodiment, the method also involves desorbing the contaminant bysonicating the functionalized silica sorbent with the adsorbedcontaminant in an organic solvent for 15-30 min, preferably 17-28 min,more preferably 18-22 min. The sonicating may involve inserting a probetip sonicator into the organic solvent, or by placing a vessel, vial, ortube holding the functionalized silica sorbent and the organic solventinto a bath sonicator. The organic solvent may be methanol, acetone,chloroform, methylene chloride, ethylacetate, and/or isopropanol.Preferably the organic solvent is ethylacetate and/or methanol, morepreferably ethylacetate. In one embodiment, the functionalized silicasorbent with the adsorbed contaminant is present in the organic solventat a concentration of 0.01-1.0 mg/μL, preferably 0.05-0.5 mg/μL, orabout 0.1 mg/μL.

In one embodiment, the method also involves detecting a desorbedcontaminant released into the organic solvent. The organic solvent anddesorbed contaminant may be fed to a gas chromatograph-mass spectrometer(GCMS) to detect and/or quantify the contaminant.

In one embodiment, a typical commercial GCMS may be used. The carriergas may be nitrogen, helium, and/or hydrogen. Preferably the carrier gasis helium with a purity of greater than 99.9 mol %, preferably greaterthan 99.99 mol %, more preferably greater than 99.999 mol %. Thestationary phase of the gas chromatography column may be comprised of amethyl siloxane (also known as methyl polysiloxane or dimethylpolysiloxane), phenyl polysiloxane, dimethyl arylene siloxane,cyanopropylmethyl polysiloxane, and/or trifluoropropylmethylpolysiloxane with a film thickness of 0.10-7 μm, preferably 0.15-1 μm,more preferably 0.2-0.5 μm. The column length may be 10-120 m,preferably 15-50 m, more preferably 25-40 m, with an inside diameter of0.08-0.60 mm, preferably 0.15-0.40 mm, more preferably 0.20-0.30 mm.

The parameters of a GCMS instrument and method of operation, includingbut not limited to flow rate, temperature, temperature gradient, runtime, pressure, sample injection, sample volume, ionization method,ionization energy, and scanning range may be adjusted by a person ofordinary skill in the art to account for differences in samples,equipment, and techniques.

The contaminant may be detected by monitoring a known elution timeand/or m/z (mass to charge ratio) for a positive signal as compared witha blank sample or with a control sample. The contaminant may bequantified with a standard addition of an internal standard. Forquantitation, known concentrations of an internal standard may be addedto a sample that is divided into aliquots. These aliquots are eachextracted and measured by GCMS. The linear response of the massspectrometer counts per concentration of a standard may be extrapolatedto quantify a contaminant. Alternatively, standards may be used tocalibrate a GCMS prior to analyzing extracted samples, for instance, byusing aliquots of known concentrations to construct a calibration curve.

In an alternative embodiment, gas chromatography may be used fordetection and/or quantitation of a contaminant without using massspectrometry. In a related embodiment, the linear trend of the peakareas of the gas chromatogram may be used for quantitation. Generally, aperson of ordinary skill in the art may be able to determine theprocedure and calculations to quantify and/or detect a contaminant basedon GCMS data.

In one embodiment, the contaminant is dichlorophenol, trichlorophenol,2,6-di-tert-butyl-4-methylphenol (26DTB4MP), 4-tert-octylphenol (4tOP),and/or benzyl-chlorophenol and may be detected and/or quantified in therange of 0.02-800 ng, preferably 0.5-700 ng, more preferably 1-600 ngper mL aqueous solution. A limit of detection (LOD) of the contaminantin the aqueous solution may be 0.05-0.50 ng/mL, preferably 0.10-0.40ng/mL, more preferably 0.20-0.35 ng/mL, where the LOD is determined witha signal-to-noise ratio of 3 (S/N=3).

The examples below are intended to further illustrate protocols forpreparing, characterizing the functionalized silica sorbent, and usesthereof, and are not intended to limit the scope of the claims.

EXAMPLE 1 Methods and Materials

Chemicals and Materials

All the tested phenols standards were ordered from SUPELCO Analytical,Germany. The 11-azidoundecyltrimethoxysilane was purchased from Gelest,Inc., USA. Tetraethyl orthosilicate reagent grade, 98% (TEOS), pluronicP123, copper (ii) sulfate, sodium ascorbate, and phenylacetylene wereprocured from Merck KGaA. PP sheet membrane (pore size of 0.2 μm, 157 μmthickness) was purchased from Membrana (Wuppertal, Germany). Highpurity-analytical grade solvents (methanol, ethanol, acetone, n-hexane,cyclohexane, dichloromethane, and carbon tetrachloride) were orderedfrom Fisher (Loughborough, UK).

Preparation of Sorbents

Synthesis of SBA-15

Mesoporous SBA-15 silica was synthesized following a previously reportedprocedure by Zhao et al. See D. Zhao, J. Feng, Q. Huo, N. Melosh, G. H.Fredrickson, B. F. Chmelka, G. D. Stucky, Triblock copolymer synthesesof mesoporous silica with periodic 50 to 300 angstrom pores, Science.279 (1998) 548-52, incorporated herein by reference in its entirety.Concisely, pluronic P123 surfactant (2 g) was dissolved in a mixture of10.3 mL concentrated HCl and 65 mL deionized water at 40° C. Aftercomplete dissolution, 4.25 mL TEOS was added and the solution wasstirred for 18 h to form the supposedly white solution of silica. Thesilica solution was then transferred into a Teflon® autoclave, andinserted into a synthesis oven at 90° C. for an additional 24 h beforecentrifuging and drying at 100° C. for 10 h. The dried powder wasdispersed in ethanol and sonicated at 65° C. for 6 h to remove thetemplate, thus forming the mesoporous SBA-15 after drying at 100° C.overnight.

Synthesis of Azide Functionalized SBA-15

A sequence of azide functionalized SBA-15 at varying azide weightpercent loading (2, 5, and 10 wt %) were prepared following theprocedure of SBA-15 synthesis with modifications. The calculated amountof 11-azidoundecyltrimethoxysilane was added dropwise to the acidicsolution containing pluronic P123 and TEOS, and the stirring wascontinued for 18 h before transferring the solution into an autoclavefor hydrothermal synthesis at 90° C. for 24 h. After removing thetemplate, the azide functionalized product was denoted xN₃-SBA-15, where“x” equals the azide weight percent.

Synthesis of 4-phenyl-1,2,3-triazole Functionalized SBA-15

After template removal in the azide functionalized SBA-15, the powderwas re-dispersed in a 1:1 mixture of 12 mL water and ethanol, followedby the addition of a stoichiometric amount of phenylacetylene, sodiumascorbate solution, and copper (ii) sulfate solution, and stirringovernight. Click reaction occurred to form the 4-phenyl-1,2,3-triazolefunctionalized SBA-15 product. The product was washed with ethanol anddeionized water several times to ensure that copper residue has beencompletely removed. ICP-MS analysis was carried out on the formedproduct to check for trace amounts of copper. The final product wasdenoted xN₃-Ph-SBA-15, where “N₃-Ph” denotes the4-phenyl-1,2,3-triazole. The synthesis strategy is been presented inFIG. 1 .

Characterization

Proton and carbon-13 magic angle spinning (MAS) solid-state NMR of thesynthesized 10N₃-Ph-SBA-15 sorbent was measured using a Bruker AVANCEIII 400 MHz wide-bore spectrometer. The surface area and pore size/porevolume of the synthesized sorbents was measured on a micromeritics ASAP2020 using N₂ adsorption-desorption at −196° C. The samples weredegassed prior to measurement at 100° C. for 6 h to remove impurities.Morphology of sorbents were recorded on a Field Emission ScanningElectron Microscope FESEM (TESCAN, LYRA 3), and the samples' elementalcomposition was determined using an energy dispersive X-ray spectrometer(EDS, Oxford Inc.) detector. Fourier Transform Infra-ray (FTIR) spectraof sorbents were measured on a Thermo Scientific NICOLET 6700spectrometer model. The samples were prepared in the form of a tinypellet by mixing small amounts of sorbent with KBr powder and theninserted in the sample holder, before recording the absorbance within ascanning range of 400-4000 cm⁻¹.

SB-μ-SPE Procedure and Analysis

Development of the SB-μ-SPE device is a simple procedure where a smallstir-bar (typically 7 mm×2 mm) and an advantageous amount of sorbent (20mg) were heat sealed inside a PP sheet bag. Proper sealing must beensured to avoid leaking of the SB-μ-SPE device during the extractionprocess. Prior to extraction, the device is conditioned via sonicationin toluene for 5 min. After conditioning, the device is inserted in aglass vial containing the sample solution and 0.5 g sodium chloride, andstirred at 600 rpm for 15 min. Later, the device is taken out, rinsedwith water, and dried using lint-free tissue. The device is theninserted into a microcentrifuge vial along with 300 μL ethyl acetate asa desorption solvent and sonicated for 20 min. After desorption, thesolvent is removed and injected into GC-MS for analysis.

Each step of the extraction process was analyzed while keeping theanalyte concentration at 200 ng mL⁻¹ in the deionized water. Theexperiments were conducted in triplicates where peak area was consideredas a quantifying parameter for the analysis. The analyzed parametersinclude type of sorbent and its dosage; extraction time; desorptionsolvent type and its volume, desorption time; and ionic strength.

GC-MS Configuration and Conditions

The GC-MS configuration and conditions for separation and quantificationof target phenols is similar to the set conditions in a recentlypublished work. See K. Alhooshani, Determination of nitrosamines in skincare cosmetics using Ce-SBA-15 based stir bar-supportedmicro-solid-phase extraction coupled with gas chromatography massspectrometry, Arab. J. Chem. (2018), doi: 10.1016/j.arabjc.2018.06.004,incorporated herein by reference in its entirety. The oven temperaturewas programmed thus: an initial temperature of 35° C. was held for 2min, then ramped at 5° C. min⁻¹ to 230° C. before holding it at 230° C.for 5 min. A 1.0 μL sample was injected using splitless mode. For theidentification of the peaks of the analytes, scan mode was run, andretention times were confirmed. The selective ion monitoring mode (SIM)was utilized for quantitative analysis by selecting the ions of therespective phenols as shown in Table 1.

TABLE 1 Target compounds, their retention time and selected target ionsfor SIM mode Retention Selected time (min) Target compounds Abbreviationtarget ions 15.304 2,4-Dichlorophenol 24DCP 63, 98, 162 15.5422,3-Dichlorophenol 23DCP 63, 126, 164 16.289 2,6-Dichlorophenol 26DCP63, 98, 162 20.397 2,4,6-Trichlorophenol 246TCP 97, 132, 196, 198 24.542,6-di-tert-butyl- 26DTB4MP 57, 265, 206, 220 4-methylphenol 26.6454-tert-Octylphenol 4tOP 52, 107, 135, 136 32.859 2-Benzyl-4- 2B4CP 140,165, 183, 218 chlorophenyl

Analytical Parameters and Real Sample Analysis

Under the tested experimental settings, the technique was assessed bydetermining linearity, LODs, repeatability, and relative recoveries. A6-point calibration curve was developed for plotting all target analytesby using ultrapure water samples spiked with known concentrations (1,50, 100, 200, 400, and 600 ng mL⁻¹) of phenols. LODs were calculatedusing signal to noise ratio method (S/N=3). To evaluate thereproducibility of the analysis, three concentrations (1, 100, and 400ng mL⁻¹) were selected from the linear range of the analyte. For eachconcentration, seven (7) trials were conducted.

The established method was applied in the analysis of phenols inwastewater samples. For real sample analysis, 10 mL unspiked real samplewas extracted using 10N₃-Ph-SBA-15 packed in SB-μ-SPE device andanalyzed using GC-MS method. Real sample analysis was also tested byspiking three concentrations (1, 100, 400 ng mL⁻¹) to the wastewatermatrix. Relative recoveries were also tested in the wastewater.

EXAMPLE 2 Results and Discussion

Characterization of 4-phenyl-1,2,3-triazole Functionalized SBA-15

The ¹H MAS NMR of 10N₃-Ph-SBA-15 shows three peaks at 1.32 ppm, 4.02ppm, and 7.29 ppm (FIG. 2A). The peak at 1.32 ppm is assigned to themethylene groups attached to the silica on one side and to the nitrogenof 1,2,3-triazole on the other side. The peak at 4.02 ppm is due to thesilanol group attached to the framework of the SBA-15, and the peak at7.29 ppm represents the three magnetically inequivalent phenyl protons.See V. B. Kazansky, A. I. Serykh, V. Semmer-Herledan, J. Fraissard,Intensities of OH IR stretching bands as a measure of the intrinsicacidity of bridging hydroxyl groups in zeolites, Phys. Chem. Chem. Phys.5 (2003) 966-969, incorporated herein by reference in its entirety. Theobserved peaks at 129.45 ppm and 148.20 ppm in the ¹³C crosspolarization MAS NMR of the sorbent shown in FIG. 2B confirm theformation of the click reaction of the azide functionalized SBA-15 andphenylacetylene, respectively. See X. Creary, A. Anderson, C. Brophy, F.Crowell, Z. Funk, Method for assigning structure of 1,2,3-Triazoles, J.Org. Chem. 77 (2012) 8756-8761, incorporated herein by reference in itsentirety. The other peaks are due to the methylene carbons and remainingsurfactants, which were not removed by the sonication treatment.

The textural properties of synthesized sorbents are presented in Table2. It was noticed that SBA-15 has the largest Brunauer-Emmett-Teller(BET) surface area (401.2 m²/g), total pore volume (0.816 cm³/g), andpore size (8.2 nm) compared to the other sorbents. It was also notedthat as the azide weight loading increases, the surface area, porevolume, and pore size decreases, which implies surface and voidblockages occurring due to azide loading. Similarly, the formed4-phenyl-1,2,3-triazole functionalized SBA-15 showed decreased surfacearea, pore volume, and pore size as follows:2N₃-Ph-SBA-15>5N₃-Ph-SBA-15>10N₃-Ph-SBA-15. As expected, the averageparticle size was observed to increase with azide loading andsubsequently with the formation of the clicked products. Thus, SBA-15has the lowest average particle size of 14.23 nm, and 10N₃-Ph-SBA-15 hasthe largest average particle size of 23.45 nm. The N₂-adsorptiondesorption isotherms of all the sorbents (FIGS. 3A and 3B) display typeIV isotherm depicting an H1 hysteresis loop, typical of mesoporousmaterials. See V. Meynen, P. Cool, E. F. Vansant, Synthesis of siliceousmaterials with micro- and mesoporosity, Microporous Mesoporous Mater.104 (2007) 26-38, incorporated herein by reference in its entirety.

TABLE 2 Textural properties of the sorbents BET External Total AverageAverage Surface Surface Pore Pore particle Area Area Volume Size sizeAdsorbent (m²/g) (m²/g) (cm³/g) (nm) (nm) SBA-15 401.2 670.0 0.816 8.214.23 2N₃-SBA-15 387.3 650.1 0.765 7.9 15.49 5N₃-SBA-15 328.1 554.40.525 6.4 18.28 10N₃-SBA-15 295.1 492.8 0.455 6.1 20.11 2N₃—Ph-SBA-15339.5 533.8 0.641 7.6 17.67 5N₃—Ph-SBA-15 299.3 499.8 0.458 6.2 20.5410N₃—Ph-SBA-15 255.8 380.9 0.416 6.5 23.45

Morphological properties of the series of xN₃-SBA-15 and xN₃-Ph-SBA-15were studied using FESEM. FIGS. 4A, 4B, and 4C represent the xN₃-SBA-15in the 2 wt %, 5 wt % and 10 wt % respectively. At 2 wt % azide, afiber-like structure was observed; however, when the azide loading wasincreased, a rod-like structure becomes more evident. FIGS. 4D-4Frepresent the xN₃-Ph-SBA-15 and show similar morphology, except for theincreased particle density, which is an indication of the clicking ofphenylacetylene to the azide group to form xN₃-Ph-SBA-15. The EDSelemental composition of the sorbents obtained from their FESEM imagesis shown in Table 3.

TABLE 3 EDX elemental composition of the sorbents Adsorbents O (%) Si(%) N (%) SBA-15 44.8 55.2 — 2N₃-SBA-15 45.1 53.6 1.4 5N₃-SBA-15 41.854.3 3.9 10N₃-SBA-15 38.9 53.2 7.9 2N₃—Ph-SBA-15 40.7 57.1 2.25N₃—Ph-SBA-15 39.4 56.9 3.7 10N₃—Ph-SBA-15 38.6 53.2 8.2

FTIR spectroscopy is one of the strong tools utilized to unveil thefunctional groups present in samples of interest. Therefore, FTIR can beused to confirm the incorporation of azide group to the SBA-15 andfurther prove the formation of xN₃-Ph-SBA-15 after the click reaction.The FTIR spectra of series of xN₃-SBA-15 and xN₃-Ph-SBA-15 are shown inFIGS. 5A and 5B, respectively. In FIG. 5A, the appearance of a new peakat 2150 cm⁻¹, which is characteristic of the stretching vibration ofazides, confirms that the azides have been successfully incorporated inthe SBA-15 framework. It was also observed that the relative peakintensity increases with the increase in the weight loading of the azidegroup. Interestingly, this azide peak completely disappears in thespectra of xN₃-Ph-SBA-15 (FIG. 5B), which confirms that the clickedproduct has been formed. Other peaks at 3,300 cm⁻¹ and 2800 cm⁻¹ can beassigned to the —OH and —CH₂ stretching vibrations, respectively.

Analysis and Application of 10N₃-Ph-SBA-15 packed SB-μ-SPE

Effect of 4-phenyl-1,2,3-triazole Loading on Phenols Extraction

Understanding the chemistry of sorbent-analytes interaction is animportant factor in the extraction of the target analytes. In apreferable embodiment the sorbent, in addition to large surface area andporosity, includes the presence of binding sites which will attractphenols. Of particular interest are the nitrogen atoms that formed thetriazole ring, which can easily bind to the hydroxyl group of thephenols via hydrogen bonding. The strength of this hydrogen bonding willdepend on the substituents attached to the target phenols. Generally,electron-donating groups tend to weaken the hydrogen bonding, whereaselectron-withdrawing groups ortho and para to the —OH of phenols tend tostrengthen the hydrogen bonding, and the more the number of theelectron-withdrawing groups at the ortho and para positions the more thestrength of the hydrogen bonding. See M. Fujio, R. T. McIver, R. W.Taft, Effects on the acidities of phenols from specificsubstituent-solvent interactions. Inherent substituent parameters fromgas-phase acidities, J. Am. Chem. Soc. 103 (1981) 4017-4029; and K. C.Gross, P. G. Seybold, Substituent effects on the physical properties andpKa of phenol, in: Int. J. Quantum Chem., Wiley-Blackwell, 2001: pp.569-579, each incorporated herein by reference in their entirety.

Moreover, the 4-phenyl-1,2,3-triazole functionalized SBA-15 beingaromatic can attract the phenols in what is termed strong host-guestinteraction via π-π interaction. See C. Li, J. Liu, X. Shi, J. Yang, Q.Yang, Periodic mesoporous organosilicas with 1,4-diethylenebenzene inthe mesoporous wall: synthesis, characterization, and bioadsorptionproperties, J. Phys. Chem. C. 111 (2007) 10948-10954, incorporatedherein by reference in its entirety. The degree of interaction, and byextension, the extraction ability, will depend on the available aromaticsites in the sorbent. In addition, the presence of the long chain“11-azidoundecyl-” and the phenyl group in the structure of thefunctionalized SBA-15 is supposedly going to enhance the extraction ofthe moderately polar phenols via non-polar-non-polar interactions.Therefore, careful observation of the extraction pattern of the targetedphenols (FIG. 6 ) shows that the highly polar phenols (24DCP, 23DCP,26DCP, and 246TCP) are extracted to nearly the same degree since all ofthem have nearly the same polarity. The slight decrease in theextraction of 246TCP is likely due to the steric hindrance that resultsfrom the three-arms chloro-substituent at ortho- and para positions. Onthe other hand, the degree of extraction of the moderately polar phenols(26DTB4MP; 4tOP, and 2B4CP) is rather dissimilar. 4tOP was extracted inan exceptionally high amount as compared to 26DTB4MP. This might bebecause 26DTB4MP has strong steric hindrance due to thetwo-ortho-positioned tertiary butyl groups and the methyl substituent atthe para position. In addition, the three substituents are good electrondonors, thus weakened the —OH polarity and consequently the hydrogenbonding with 1,2,3-triazole. The observed extraction performance of thesorbents for the seven phenols shown in FIG. 6 follows the trend10N₃-Ph-SBA-15>5N₃-Ph-SBA-15>2N₃-Ph-SBA-15>SBA-15. This is because the10N₃-Ph-SBA-15 sorbent has the largest active sites for extraction whencompared to the other sorbents, even though the increase in extractionis not proportional to the 4-phenyl-1,2,3-triazole group loading sincethe surface area and pore size/pore volume of the sorbents decreases asthe 4-phenyl-1,2,3-triazole loading increases. This results in someactive sites becoming not accessible for the extraction of phenols.

Overall, 4-phenyl-1,2,3-triazole loading increases the extractionperformance, thus 10N₃-Ph-SBA-15 was selected for further extractionexperiments.

Sorbent Dosage

The quantity of sorbent utilized in the phenol extraction is probable tohave some effect on the extraction efficiency. It is expected that thelarger the sorbent dosage, the greater the number of active sitesavailable for phenol extraction, hence the better the extractionexperience. Thus, by keeping other extraction variables constant, theamount of 10N₃-Ph-SBA-15 sorbent was varied between 5 and 25 mg. It wasobserved that as the sorbent amount is increased, its extractionperformance also increased for the seven different phenols (FIG. 7 ).The maximum extraction was achieved at 20 mg of the 10N₃-Ph-SBA-15sorbent, thus was selected as the amount for further extraction process.Further increase in the sorbent amount shows no significant effect onextraction of phenols, probably because with higher amounts of sorbents,higher extraction and desorption times would be also required.

Desorption Solvent

The choice of desorption solvent is crucial to achieving excellentanalyte desorption. Typically, the polarity of the analytes is acriterion to choosing a desorption solvent, and since phenols arerelatively polar, by default the best desorption solvent is likely to bepolar. Therefore, six different polar solvents: methanol, 2-propanol,acetone, methylene chloride, chloroform, and ethyl acetate were used asdesorption solvent. As shown in FIG. 8 , ethyl acetate proved to be thebest solvent for the desorption of phenols from the 10N₃-Ph-SBA-15sorbent. Ethyl acetate, which is a moderately polar solvent, has shownexcellent desorption for both highly polar and relatively less polarphenols during ultrasonication desorption steps. Thus, it is consideredthe desorption solvent to use.

Volume of Desorption Solvent

It is anticipated that solvent volume applied in desorbing analytesalters the efficiency and reproducibility of the desorption. Here, theeffect of solvent volume was assessed in the range of 200-500 μL. It wasobserved that the largest desorption for the analytes was achieved using300 μL for all the extracted phenols (FIG. 9 ). Above 300 μL solventvolume, the desorption proficiency decreases proportionately with theboost in volume. This observed trend is probably due to the dilution ofthe analytes at desorption volumes above 300 μL, thus resulting in lowerresponse during analysis. On the contrary, lower desorption volumes(<300 μL) result in partial immersion of the SB-μ-SPE device, hencedecreased desorption efficiency, and irreproducibility of the analysisin some cases. Therefore, 300 μL was chosen as the best desorptionvolume for subsequent extraction procedures.

Salting Out Effect

Depending upon the nature of the analyte, the salting out effect wasevaluated. Generally, the addition of salt can result in enhancedanalyte extraction or vice versa. By adding salt to the sample solution,it is anticipated that the target analytes' solubility in aqueoussolution will decrease, especially if the target analytes are polarcompounds. This will consequently result in increased extraction of theanalytes. In this extraction experiment, 0.5-3 g of sodium chloride(NaCl) was added to the sample solution, and it was noticed that maximumextraction of the analytes is reached with 0.5 g of NaCl for the studiedphenols (FIG. 10 ). Further addition of the salt had no substantialeffect on the phenols extraction. Therefore, 0.5 g was considered as theamount of NaCl to use in this procedure.

Extraction Time

SB-μ-SPE is an equilibrium based, non-exhaustive technique; therefore,extraction time is a vital parameter to examine. The extraction of theanalytes generally increases with increasing time until equilibrium isestablished. In the present disclosure, extraction time was variedbetween 5 min to 40 min, and it was found that 20 min is the bestextraction time as shown in FIG. 11 .

Desorption Time

Alike extraction time, desorption time is also an imperative parameterin maximization of the extraction procedure. The desorption was done bysubmerging the analyte-bound SB-μ-SPE in ethyl acetate followed bysonication. The sonication time was varied between 5-30 min. It wasobserved that as the desorption time increases, the desorption of thetarget analytes into the ethyl acetate also increases until 20 min (FIG.12 ). After that, the desorption remains stable up to 30 min. Therefore,20 min was selected as the desorption time to use.

Stirring Rate

The mass transfer of analytes to and from the SB-μ-SPE device may alsobe affected by the stirring rate during the extraction process.Therefore, the stirring rate was varied between 300-1200 rpm.Interestingly, no significant effect in the extraction efficiency wasnoticed within the varied stirring rate.

Analytical Parameters and Real Sample Analysis

The extraction of the phenols using 10N₃-Ph-SBA-15 sorbent packed insideSB-μ-SPE device and its GC-MS analysis was evaluated for differentanalytical parameters under the experimental conditions chosen by theabove tests. The analysis was found to have a linear response between 1ng mL⁻¹ to 600 ng mL⁻¹. Excellent linearity was observed from thecalibration curve with R² ranging between 0.9941 and 0.9989. Threeconcentrations were selected out of the linear calibration curve, andseven trials were designed for each concentration to assess thereproducibility of the analysis. The analysis has shown goodreproducibility with less than 7.5% difference. The extraction andanalysis overall produced lower LODs between 0.23 to 0.37 ng mL⁻¹(S/N=3) as presented in Table 4.

TABLE 4 Analytical features of the method Matrix effect and extractionefficiency (Mean relative RSDs (%) Linear recoveries n = 3) (n = 7)range* LOD 1 100 400 1 100 400 Compound (ng/mL) R² (ng/mL) ng/mL ng/mLng/mL ng/mL ng/mL ng/mL 24DCP 1-600 0.9989 0.24 96.8 98.8 94.5 4.5 3.93.3 23DCP 1-600 0.9989 0.25 95.3 96.5 95.5 7.5 6.8 6.6 26DCP 1-6000.9941 0.23 92.5 89.3 88.5 6.6 5.1 5.2 246TCP 1-600 0.9951 0.30 95.898.2 99.2 5.5 4.5 4.1 26DTB4MP 1-600 0.9984 0.37 97.8 98.5 98.8 3.5 4.52.3 4tOP 1-600 0.9977 0.24 88.6 88.9 90.8 5.2 5.1 4.8 2B4CP 1-600 0.99720.29 93.5 95.8 97.8 7.2 6.2 5.1

The analysis was also tested in a real wastewater sample. The selectedphenols were not detected in the wastewater sample; however, wastewaterspiked with 1, 100, and 400 ng mL⁻¹ concentrations have shown highrelative recoveries in the range of 88.5 to 99.2%. The chromatogramshowing the wastewater unspiked and spiked with 1 ng mL⁻¹ is presentedin FIG. 13 . Here, peak 1=2,4-dichlorophenol; peak 2=2,3-dichlorophenol;peak 3=2,6-dichlorophenol; peak 4=2,4,6-trichlorophenol; peak5=2,6-di-tert-butyl-4-methylphenol; peak 6=4-tert-octylphenol; peak7=2-benzyl-4-chlorophenol. Comparison of this extraction approach withrecently published work presented in Table 5 showed that with this novelsorbent in SB-μ-SPE, phenols can be extracted with comparable results tothe other methods.

TABLE 5 Comparison of SB-μ-SPE with published methods No. of LinearRange phenols Real sample LODs RSDs Method (μg L⁻¹) analyzed type (μgL⁻¹) (%) Ref. SMSME¹- 5-150 7 Agricultural 1-4 ≤10.1 [35] HPLC and lakewater Fiber SPME²- 0.1-100  7 Honey 0.06-0.2   3.8-12.7 [36] GCMSsamples SBSE³-HPLC- 0.25, 0.5, 8 Lake and river 0.08-0.30 4.3-9.4 [37]UV 1 to 500 sample ASE-DLLME⁴- 6.1-3080  4 Soil sample 0.06-1.83 <10[38] GCMS MAMDSPE⁵- 2-80  8 Tap water 1.3 <13-17  [39] HPLC 10N₃—Ph-SBA-1-600 7 Wastewater 0.23-0.37 2.3-7.5 This 15-based SB-μ- work SPE-GCMS¹Supramolecular solvent based microextraction ²Fiber solid phasemicroextraction ³Stir-bar sorptive extraction ⁴Accelerated solventextraction-dispersive liquid-liquid microextraction ⁵Magnetic assistedmicro-dispersive solid phase extractions

An effective strategy for the extraction of highly to moderately polarphenols in water samples was shown above by synthesizing series of4-phenyl-1,2,3-triazole functionalized SBA-15 sorbents (xN₃-Ph-SBA-15;x=2-10 wt. %) via two steps: azide functionalization of SBA-15 and itsclick reaction with phenylacetylene. The formed sorbents, which have theblend of both polar (1,2,3-triazole) and non-polar (long chain alkylgroups) sites were characterized using magic angle spinning NMR, surfacearea, pore size/pore volume N₂ adsorption-desorption isotherms, scanningelectron microscope, and Fourier transform infra ray spectroscopy. Thesurface area and pore size/pore volume decreases with increasing loadingof 4-phenyl-1,2,3-triazole. The sorbents were used in a stirbar-supported micro-solid-phase extraction (SB-μ-SPE) method for phenolsin water samples, in combination with gas chromatography-massspectrometry (GC-MS). In a preferred embodiment, 10N₃-Ph-SBA-15 sorbentwas used with a 20 mg dosage; 20 min extraction time; 300 μL of ethylacetate as desorption solvent, 20 min desorption time; and ionicstrength set at 0.5 g NaCl. The approach provided a linear detectionrange for all tested phenols with R² value up to 0.9989 and detectionlimit (LOD) of 0.23-0.37 ng mL⁻¹. Relative standard deviation (RSD)values determined at varied concentrations were within 2.3-7.5%. Withthis developed 4-phenyl-1,2,3-triazole functionalized SBA-15 sorbents,the analysis of phenols in wastewater matrix has successfully presentedrelative recoveries in the range of 88.5 to 99.2%.

The invention claimed is:
 1. An azole functionalized silica sorbentcomprising: porous silica nanoparticles having a surface functionalizedwith a 4-phenyl-1,2,3-triazole conjugated system attached by an undecylgroup, and wherein the porous silica nanoparticles have an averageparticle size of 10-80 nm.
 2. The azole functionalized silica sorbent ofclaim 1, wherein the porous silica nanoparticles are clustered inagglomerates having an average diameter of 1-4 μm.
 3. The azolefunctionalized silica sorbent of claim 1, wherein the porous silicananoparticles have an average pore size in a range of 4-9 nm.
 4. Theazole functionalized silica sorbent of claim 1, wherein the poroussilica nanoparticles have a BET surface area of 200-380 m²/g.
 5. Theazole functionalized silica sorbent of claim 1, wherein the poroussilica nanoparticles have a total pore volume in a range of 0.380-0.700cm³/g.
 6. The azole functionalized silica sorbent of claim 1, which has3-12 wt % N relative to a total weight of the azole functionalizedsilica sorbent.
 7. The azole functionalized silica sorbent of claim 1,which has 50-58 wt % Si relative to a total weight of the azolefunctionalized silica sorbent.